“Green coffee" refers to the raw or unroasted seeds (beans) of Coffee fruits. Green coffee beans are cleaned, dried, roasted, ground, and brewed to produce coffee. Coffee contains hundreds of components, each of which may have potential and independent pharmacological effects.

Coffee is a notable source of caffeine. However, coffee’s effects on glycemic control and weight loss have been attributed to its other components, including chlorogenic acid, quinides, lignans, and trigonelline, all of which have been shown to improve glucose metabolism in animal studies.

Chlorogenic acid has specifically been shown to inhibit an enzyme, glucose-6-phosphatase, that promotes the formation of glucose (sugar) in the liver. Hence, chlorogenic acid in coffee may be responsible, at least in part, for the reduced risk of glycemic disorders, like diabetes, with long-term coffee consumption.

It may also be the source of coffee’s anti-obesity effects. Various studies have suggested that chlorogenic acid slows absorption of fat from food intake and also activates metabolism of extra fat. Unfortunately, traditional brewed coffee doesn’t serve as a good source of chlorogenic acid. While roasting green coffee beans removes its naturally bitter taste, it also removes a significant portion of chlorogenic acid. Hence, green coffee beans remain one of the best natural sources for chlorogenic acid.